Patent GB-889851-A (GB)
Title: Fibrous reinforcements and rubber articles incorporating the same
IPC: B60C9/00
Filed: 1960-06-27
Abstract: In a fibrous structure of a linear terephthalate polyester, the polyester has a relative viscosity (defined as the ratio of the viscosity of a 10% by weight solution of the polymer in a mixture of 10 parts by weight of phenol and 7 parts by weight of 2,4,6-trichlorophenol to the viscosity of the phenol-2,4,6-trichlorophenol mixture at 25 DEG C.) of at least 25 and the fibrous structure having a concentration of free carboxyl groups of less than 15 equivalents per million grams and an ether concentration of not more than 3 mol. per cent.  The term "free carboxyl groups" includes both the ionized and unionized carboxyl groups.  The term "ether concentration" is directed towards the mol. percentage of aliphatic groups containing ether linkages.  Polymers of the required free carboxyl concentration may be made either by "capping" free carboxyl groups of polyesters or by solid phase polymerization, e.g. a polymer formed by the process of Specification 578,079 is heated in a finely divided state in a dry inert gas at a temperature below the stick temperature of the polymer.  Specified glycols from which the linear polyesters are made are those containing from 2 to 18 carbon atoms, e.g. ethylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,4-butanediol, trans-p-hexahydroxylene glycol, bis-p-(2-hydroxyethyl)benzene, 4,41-bis(b -hydroxyethyl)diphenyl and 4,41-bis-(b -hydroxyethyl)dodecahydrodiphenyl.  Up to 15 mol. per cent of the recurring structural units may contain adipate, sebacate, iso-phthalate, dibenzoate or hexahydroterephthalate radicals.  In the Examples:- (1) dimethyl terephthalate and ethylene glycol are reacted in the presence of manganous acetate to form a monomer which is condensed in the presence of antimony oxide, the resultant polymer being melt spun and drawn, corded and treated with diazomethane to reduce the free carboxyl content, (II) polyethylene terephthalate ribbon is finely divided and heated under an inert gas to increase the molecular weight and reduce the free carboxyl content and (IV) dimethyl terephthalate and ethylene glycol are reacted in the presence of manganous acetate and antimony oxide to form the monomer which is condensed in the presence of phosphoric acid and titanium dioxide, the resultant polymer being spun into fibres.  Examples (V) and (VI) describe the coating of polyethylene terephthalate cord with an adhesive composition comprising an aqueous dispersion of the bis-phenol adduct of methylene bis-(4-phenylisocyanate), gum tragacanth and a mixture of a vinyl pyridine latex and a butadiene latex, the coated product being used (V) in the manufacture of tyres (VI) in the preparation of a V-belt. Specifications 574,903, 773,778 and U.S.A.  Specification 2,534,028 also are referred to.ALSO:In a fibrous structure of a linear terephthalate polyester, the polyester has a relative viscosity of at least 25 and the fibrous structure has a concentration of free carboxyl groups of less than 15 equivalents per million grams and an ether concentration of not more than 3 mol per cent.  The requisite free carboxyl concentration may be attained by immerising the fibres in diazomethane at room temperature. Example V describes the coating of polyethylene terephthalate cord with an adhesive composition comprising an aqueous dispersion of the bis-phenol adduct of methylene bis-(4-phenylisocyanate), gum tragacanth and a mixture of a vinyl pyridine latex and a butadiene latex, the dipped cord being heated and used to reinforce tyres and V-belts. Specifications 574,903, 578,079 and 773,778 are referred to.